Where do you find "virgin" small primer .45 cases, who makes it, and why did you specifically buy it?
Personally, not having to switch primer system would make small primer brass somewhat attractive, as that is the only large primer cartridge I load regularly, though I still have "need" for the occasional 10mm Auto, .45 Colt, .45 Win Mag, and .44 Mag round.
.45 Auto is the easiest round to load. It doesn't suffer from a severely tapered case, like 9x19, so it goes through the dies easier. Being a short squat case, it is easy to inspect the powder charge in the case. It just doesn't get any easier than .45 Auto in terms of loading. Gamestalker: did you really mean that a .45 Auto case is harder to inspect than a 9x19?
The main thing about virgin cases is that they have no soot to "lubricate" bullet seating and can be hard to extract from the expander die. Beyond that, what, exactly, do you think could be different?
Yes, new cases need to be sized. They may not be round and they may not be at the proper ID for bullet seating.
All cases need to be chamfered at least once (and after every trimming, for bottleneck cases). In fact, a properly chamfered and expanded case will not require case mouth flare for seating jacketed bullets.
Aside: I hate the use of "casing" for cases as much as I hate OAL for COL (cartridge overall length, which by its name is specific to the loaded cartridge). However, reading my Dillon manual, I note that they use OAL all the time (though OAL can refer to anything being measured and is not a specific term like COL), so I imagine that casing will start being used also. As far as I as concerned, casings are used for sausage making and around windows, But the use of specific terminology seems to be losing ground even within the industry where it should be required.
It is like the use of "pill" or "bullet head" for bullet or, even worse, the use of "bullet" to refer to a loaded round. It is also like the use of "clip" for magazine, where the two terms refer to two very different things, but even the military is getting into the "clip" thing--and they should KNOW the difference.